diff --git a/src/pai_rag/integrations/readers/pai/pai_data_reader.py b/src/pai_rag/integrations/readers/pai/pai_data_reader.py
index 8c3e28cd..0f9aab42 100644
--- a/src/pai_rag/integrations/readers/pai/pai_data_reader.py
+++ b/src/pai_rag/integrations/readers/pai/pai_data_reader.py
@@ -149,7 +149,8 @@ def get_input_files(
         )
 
     file_metadata_map = {
-        file: default_file_metadata_func(file_path=file) for file in input_files
+        str(file): default_file_metadata_func(file_path=str(file))
+        for file in input_files
     }
     return input_files, file_metadata_map